# -*- coding: utf-8 -*-
# util.py
# Copyright (C) 2016 LEAP Encryption Acess Project
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""
Handy common utils
"""
import os
import platform
import sys

from twisted.logger import Logger

from leap.common.files import which


STANDALONE = getattr(sys, 'frozen', False)

logger = Logger()


def here(module=None):
    global STANDALONE

    if STANDALONE:
        # we are running in a |PyInstaller| bundle
        return sys._MEIPASS
    else:
        dirname = os.path.dirname
        if module:
            return dirname(module.__file__)
        else:
            return dirname(__file__)


def get_gpg_bin_path():
    """
    Return the path to gpg binary.

    :returns: the gpg binary path
    :rtype: str
    """
    global STANDALONE
    gpgbin = None

    if STANDALONE:
        if platform.system() == "Windows":
            gpgbin = os.path.abspath(
                os.path.join(here(), "apps", "mail", "gpg.exe"))
        elif platform.system() == "Darwin":
            gpgbin = os.path.abspath(
                os.path.join(here(), "apps", "mail", "gpg"))
        else:
            gpgbin = os.path.abspath(
                os.path.join(here(), "..", "apps", "mail", "gpg"))
    else:
        try:
            gpgbin_options = which("gpg", path_extension='/usr/bin/')
            # gnupg checks that the path to the binary is not a
            # symlink, so we need to filter those and come up with
            # just one option.
            for opt in gpgbin_options:
                # dereference a symlink, but will fail because
                # no complete gpg2 support at the moment
                # path = os.readlink(opt)
                path = opt
                if os.path.exists(path) and not os.path.islink(path):
                    gpgbin = path
                    break
        except IndexError as e:
            logger.debug("couldn't find the gpg binary!: %s" % (e,))

    if gpgbin is not None:
        return gpgbin

    # During the transition towards gpg2, we can look for /usr/bin/gpg1
    # binary, in case it was renamed using dpkg-divert or manually.
    # We could just pick gpg2, but we need to solve #7564 first.
    try:
        gpgbin_options = which("gpg1", path_extension='/usr/bin')
        for opt in gpgbin_options:
            if not os.path.islink(opt):
                gpgbin = opt
                break
    except IndexError as e:
        logger.debug("couldn't find the gpg1 binary!: %s" % (e,))

    if gpgbin is None:
        logger.debug("Could not find gpg1 binary")
    return gpgbin